Effect of an extendable slat on the stall behavior of a VR-12 airfoil

Experimental and computational tests were performed on a VR-12 airfoil to determine if the dynamic-stall behavior that normally accompanies high-angle pitch oscillations could be modified by segmenting the forward portion of the airfoil and extending it ahead of the main element. In the extended position the configuration would appear as an airfoil with a leading-edge slat, and in the retracted position it would appear as a conventional VR-12 airfoil. The calculations were obtained from a numerical code that models the vorticity transport equation for an incompressible fluid. These results were compared with test data from the water tunnel facility of the Aeroflightdynamics Directorate at Ames Research Center. Steady and unsteady flows around both airfoils were examined at angles of attack between 0 and 30 deg. The Reynolds number was fixed at 200,000 and the unsteady pitch oscillations followed a sinusoidal motion described by alpha = alpha(sub m) + 10 deg sin(omega t). The mean angle (alpha(sub m)) was varied from 10 to 20 deg and the reduced frequency from 0.05 to 0.20. The results from the experiment and the calculations show that the extended-slat VR-12 airfoil experiences a delay in both static and dynamic stall not experienced by the basic VR-12 airfoil

Digital media infrastructures: pipes, platforms, and politics

Over the past decade, a growing body of scholarship in media studies and other cognate disciplines has focused our attention on the social, material, cultural, and political dimensions of the infrastructures that undergird and sustain media and communication networks and cultures across the world. This infrastructural turn assumes greater significance in relation to digital media and in particular, the influence that digital platforms have come to wield. Having “disrupted” many sectors of social, political, and economic life, many of the most widely used digital platforms now seem to operate as infrastructures themselves. This special issue explores how an infrastructural perspective reframes the study of digital platforms and allows us to pose questions of scale, labor, industry logics, policy and regulation, state power, cultural practices, and citizenship in relation to the routine, everyday uses of digital platforms. In this opening article, we offer a critical overview of media infrastructure studies and situate the study of digital infrastructures and platforms within broader scholarly and public debates on the history and political economy of media infrastructures. We also draw on the study of media industries and production cultures to make the case for an inter-medial and inter-sectoral approach to understanding the entanglements of digital platforms and infrastructures

Security analyst networks, performance and career outcomes

Authors' draft. Final version to be published in The Journal of Finance. Available online at http://onlinelibrary.wiley.com/Using a sample of 42,376 board directors and 10,508 security analysts we construct a social network, mapping the connections between analysts and directors, between directors, and between analysts. We use social capital theory and techniques developed in social network analysis to measure the analyst’s level of connectedness and investigate whether these connections provide any information advantage to the analyst. We find that better-connected (better-networked) analysts make more accurate, timely, and bold forecasts. Moreover, analysts with better network positions are less likely to lose their job, suggesting that these analysts are more valuable to their brokerage houses. We do not find evidence that analyst innate forecasting ability predicts an analyst’s future network position. In contrast, past forecast optimism has a positive association with building a better network of connections

Confrontation of viewpoints in a concurrent engineering process

We present an empirical study aimed at analysing the use of viewpoints in an industrial Concurrent Engineering context. Our focus is on the viewpoints expressed in the argumentative process taking place in evaluation meetings. Our results show that arguments enabling a viewpoint or proposal to be defended are often characterized by the use of constraints. One result involved the way in which the proposals for solutions are assessed during these meetings. We have revealed the existence of specific assessment modes in these meetings as well as their combination. Then, we show that, even if some constraints are apparently identically used by the different specialists involved in meetings, various meanings and weightings are associated with these constraints by these different specialists

Parenting Science Gang : radical co-creation of research projects led by parents of young children

Background Parents are increasingly searching online for information supported by research but can find it difficult to identify results relevant to their own experiences. More troublingly, a number of studies indicate that parenting information found online often can be misleading or wrong. The goal of the Parenting Science Gang (PSG) project was to use the power of the Internet to help parents ask questions they wanted to have answered by scientific research and to feel confident in assessing research evidence. Methods By using Facebook to recruit groups and facilitate interactions, PSG was able to engage fully the target public of parents of young children in the radical co-production of scientific studies, while not creating an undue burden on time or restricting participants due to disability, financial status or location. By giving parents true partnership and control of creation of projects, PSG ensured that the chosen questions were ones that were of most relevance and interest to them. Results This paper presents a summary of eight projects, with three in more detail, designed and implemented by PSG Facebook groups in collaboration with experts. Most projects had health related themes, often prompted by dissatisfaction with treatment of parents by health professionals or by feelings of being marginalised by pregnancy and motherhood, as well as by the lack of evidence for their questions and concerns. The PSG approach meant that these frustrations were channelled into actions. All eight of the PSG groups engaged in meaningful interactions with experts and co-produced studies with the groups defining the questions of interest. Conclusions This radically user-led design meant that the PSG staff and the collaborating experts had to live with a high degree of uncertainty. Nevertheless, PSG achieved its goal of academically productive, truly co-produced projects, but as important were the positive effects it had on many of the participants, both parents and experts. At the point of writing this paper, PSG projects have led to outputs including at least eight papers published, in press or in preparation, seven conference presentations, testimony to the Infant Feeding All-Party Parliamentary Group, and with more to come